Svetlana Kuznetsova reveals the factors behind Roger Federer's success at 36

Two-time Grand Slam champion Svetlana Kuznetsova has hailed Roger Federer for winning the Australian Open and going back on top of the ATP rankings for the fourth time in his career. The Russian is recovering from a wrist injury for which she had to be operated on last November.

The 36-year-old became the oldest world number one in tennis following his quarter-final victory over Robin Haase at Rotterdam, the tournament he went on to win for the third time in his career. He broke Andre Agassi's long standing record – the American was 33 when he reached the summit in 2003.

Federer beat Rafael Nadal to the number one rank, with the players only separated by a mere 155 points before Rotterdam. The Spaniard had managed to hold on to his spot at the top after reaching the quarter-finals of the Australian Open, which was eventually won by Federer. His win at Melbourne marked his 20th singles Slam, only the fourth player to do so in history.

Kuznetsova is amazed at how Federer has managed to reach the level he has at 36 but attributed a lot of the Swiss ace's success to his wife Mirka who was beside him through thick and thin. She also had great words for Federer's team, who made it easier for him to keep organised through all the problems, something that other players have had to face.

"Roger is the best, it's unbelievable. I'm so proud to be his fan. This life it's burning you out a lot. I think Roger he learned over the years, and probably for sure with help of Mirka, and having a great team around him, organising all the travels and somehow he doesn't get so tight and so many problems like other players do," Kuznetsova told Sport360.

"It's smoother for him and of course his potential and talent, everything how it's organised and how he is, and his greatness on the tennis court it works for him much better, so that's why he's so good at that age."